Synthesis and structures of crystalline lithium 1-azaallyls and a 1,3-diazaallyl derived from Li{CH(SiMe3)(SiMe3-n(OMe)n)}(n=1 or 2) and Li{CH(SiMe2OMe)2} and RCN (R = tBu, Ph, 2,5-Me2C6H3, or Ad)

Crystalline [Li{N(SiMe2OMe)C(tBu)C(H) (SiMe3)}]2 (5), [Li{N(SiMe2OMe)C(Ph)C(H) (SiMe3)}]2 (6), [Li{N(SiMe2OMe)C (C6H3Me2-2,5)NC(C6 H3Me2-2,5)C(H)(SiMe3)} (TMEDA)](7), [Li{N(SiMe(OMe)2)C(tBu)C(H) (SiMe3)}(THF)]2 (8), Li{N(SiMe(OMe)2) C(Ph)C(H)(SiMe3)}(TMEDA) (9) and [Li{N(SiMe2OMe) C(tBu)C(H)(SiMe2OMe)}]2 (10) were readily obtained at ambient temperature from (i) [Li{CH(SiMe3) (SiMe2OMe)}]8 (1) and an equivalent portion of RCN (R=tBu (5), Ph (6) or 2,5-Me2C6 H3 (7)); (ii) [Li{CH(SiMe3)(SiMe(OMe)2)} ]∞ (2) and an equivalent portion of tBuCN (8) or PhCN (9); and (iii) [Li{CH(SiMe2OMe)2}] ∞ (3) and one equivalent of tBuCN (10). Reactions (i) and (ii) were regiospecific with SiMe3-n(OMe)n SiMe3 in 1,3-migration from C (in 1 or 2)→N. The 1-azaallyl ligand was bound to the lithium atom as a terminally bound κ1-enamide (8 and 10), a bridging η3- 1-azaallyl (6), or a bridging κ1-enamide (5). The stereochemistry about the C=C bond was Z for 5, 8 and 10 and E for 7. X-ray data are provided for 5, 6, 7, 8 and 10 and multinuclear NMR spectra data in C6D6 or C6D5 CD3 for each of 5-10. © 2003 Elsevier Science B.V. All rights reserved.